I was channel flipping yesterday and ta-da, here’s an Space Shuttle Astronaut (don’t know his name) going for the Million dollar question…

The question was: “How many Common Factors do the numbers 28 and 32 have?”

He said two (2 and 4) and the answer was three (1, 2, and 4).

Is that right? I always thought that the number one was not included for Common Factors. For example, relative prime numbers (such as 4 and 15) have no Common Factors by definition. According to Fox, they always will have at least one.